Safety guard for punch presses



March 6, 1934. p ER|K5EN 1,950,233

SAFETY GUARD FOR PUNCH PRESSES Filed April 21, 1931 3 Sheets-Sheet l R31 AZkZw 13 44%? .5 M 8/ MM March 1934- P. A. ERIKSEN SAFETY GUARD FOR PUNCH PRESSES Filed Apiil 21, 1931 3 Sheets-Sheet 2 March 6, 1934. ERlKsENr 1,950,233

SAFETY GUARD FOR PUNCH PRESSES Filed April 21. 1931 3 Sheets-Sheet 3 Patented Mar. 6, 1934 UNITED STATES PATENT OFFICE,

9 Claims.

The principal object of this invention is to provide a new and useful safety guard for punch presses or the like.

Another object of the invention is to construct a safety guard for punch presses which will prevent the movement of the press when the hands of the operator are in the throat of the press.

A further object of the invention is to provide a gate which must be actuated to lock the mechanism before the operator can place a blank in position on the lower die.

The invention further resides in certain features and details of construction set forth hereinafter and shown in the accompanying drawings,

'in which:

Figure 1 is a side elevation view showing a punch press constituting the invention;

Fig. 2 is a front elevation view of the disclosure in Fig. 1;

i Fig. 3 is an enlarged detail view showing the safety gate in the closed position;

Fig. 4 is a view similar to that shown in Fig. 3, showing the safety gates in the open position;

Fig. 5 is a sectional view on line 5-5, Fig. 2;

Fig. 6 is an enlarged fragmentary view showing the detail construction of the clutch releasing mechanism;

Fig. 7 is a plan view of the disclosure of Fig. 6;

Fig. 8 is an end elevation view of the disclosure Iof Fig. 6;

Fig. 9 is a view in perspective showing the pivotally mounted stop member normally providing a fulcrum for the clutch releasing lever; and

Fig. 10 is a detached perspective view of the .release plate.

Referring to the drawings, the invention in the present instance is used in conjunction with an ordinary punch press 1 having a throat 2 in which is mounted a fixed die 3 and a movable die 4, the said movable die 4 being vertically moved by the connecting rod 5 which is connected at its upper extremity to a shaft 6. Power is applied to the movable die 4 by a motor 7 having a gear 8 mounted on the shaft thereof and meshed with teeth 9 formed on the outer surface of a fly wheel 10 which is mounted on the aforementioned shaft 6 at the opposite extremity thereof from the connecting rod 5. The motor is preferably mounted above the punch press 1 on suitable brackets 11.

In ordinary operation of a punch press, it is necessary that the article to be worked be placed on the lower die manually by the operator, after which a treadle is actuated against a spring which releases a clutch mechanism permitting the shaft of the press to make one revolution, forcing the punch or upper die to descend and contact with the articles placed on the lower die by the operator. Very often, such an operator becoming skilled, and when on a piece rate production basis,

in an endeavor to obtain a maximum productive output for a given period, actuates the treadle before his hands are entirely removed from the vicinity of the lower die and are not removed from the path of the descending upper die. This practice in the past has resulted in numerous ac- 66 cidents by the loss of a finger or an entire hand. With this situation in mind, I have invented a new and useful safety guard for machines of thistype, which prevents the release of the clutch mechanism during the period that the operators (0 hands are in the vicinity of the lower and upper dies 3 and 4 respectively.

In the present instance the clutch mechanism comprises a segmental friction shoe 12, the inner surface of which normally contacts with the sur- (5 face of the shaft 6 to prevent the rotation thereof. The clutch 12 is released from contact with the shaft 6 by actuating the foot treadle 13 against a spring 14, the said treadle acting through the rod 15, the lever 16, and the rod 17. against the no action of a'spring 18, secured on the rod 17 by a collar 19, to pull the clutch shoe 12 out of contact with the said shaft 6. To effectively release the clutch 12, the lever 16 must be provided with a fulcrum to prevent the said lever from merely as pivoting about the point 20, and this invention relates primarily to the mechanism and apparatus controlling the movement of such a fulcrum into or out of the path of the said lever 16. While a certain type of punch press has been described, it will be understood that the invention can be applied to other forms of presses and punches without departing from my invention.

The safety guard comprises a cage 22 having permanently fixed wire screen sides 23. The front 9:; portion of the cage 22 is preferably formed in two parts, such as the pivotally mounted gates 24 and 25 respectively, which are preferably composed of transparent material to permit the operator of the punch press to view the punching operation and to facilitate the correct positioning of the material upon the die. In the present instance, the gates 24 and 25 are mounted to pivot respectively in the direction of the arrows shown in conjunction with the gates in Fig. 5 of the drawings. The gates in the present instance are rigidly mounted on the shafts 26 and 2'7 respectively. Secured to the shaft 26 is a lever 28. One arm of the lever is connected.- to an arm 33 on the shaft 27 by a link 30. On the long arm of the lever 28 is a weight 29 which tends to normally keep the gates in the closed position. An arm 34 is secured to the end of the shaft 26 opposite the lever 28 and is connected at 35 to the forward extremity of a rod 36. A release plate 3'7 having a slot 38 therein, is pivoted at 4'7 at the other end of the rod 36. A stop lever 40 having a horizontal portion 41 and a stop element 42, is pivotally mounted at 43 on a supporting bracket 44 which is secured to the punch press 1. Apin 45 at the opposite end of the stop member 40 from the vertical element 42 is positioned in the slot 38 formed in the plate 3'7 secured to the rod 36. In

the present instance the lower end of the stop 42 is bevelled to provide a suitable edge engagement with the notch 46 in the rear end of the lever 16 thus eliminating the possibility of the stop 42 slipping out of the path of the lever 16, see Fig. 6.

20 The release plate 3'7 has a lip 48 which engages the rod 36 and holds the plate in engagement with the pin 45 and when it is desired to disengage the safety mechanism the plate is raised by a handle 39 a sufficient distance for the lip to clear the rod 36, when it can be turned on its pivot to release the pin 45. In some instances the rod may be permanently connected to the stop member 40. l i In operating the punch press with the safety soc uard installed, the operator of the machine places the material to be worked upon on the lower die 4, by pushing inwardly the lower gate 24. The gate 25 is simultaneously raised as the two gates are connected by the link 30. The said aai ates 24 and 25respectively, assume positions when opened, substantially as shown in Fig. 4. The opening of the gates 24 and 25 moves the lever 28 to the position shown in Fig. 4, and causes the arm 34, which is rigidly connected to the shaft 26, to move to the position shown in the above figure, (Fig. 4) thus moving the bar 36 forwardly of the machine, to a position substantially as shown in dotted lines in Fig. 7 of the drawings, the plate 3'7 on the bar 36 being connected to member 5 40 by the pin 45, moves the stop 40 to a position shown in dotted lines in Fig. '7, and out of the path of the lever 16.

With the vertical element 42 of the stop member 40 removed from the path of the lever 16, the 5 actuation of the treadle 13 will be ineffective to release the clutch mechanism 12, the said lever 16 merely pivoting about the point 20. After the piece is in position between the dies the hands of the operator are withdrawn and the gates 24 and 25 will be automatically closed by the weight 29 when the gates 24 and 25 are in the closed position and the bar 36 is returned to the position shown in solid lines in Fig. '7 through the action of the levers 33 and 30 respectively, the vertical element 42 of the stop member 40 is moved into the path of the lever 16 and when the treadle 13 is actuated, the stop 42 will act as a fulcrum for the lever 16, the bevelled end of the said stop 42 engaging the notch 46 to prevent said stop from 65, slipping out of contact with said lever 16. The clutch 12 will be released from contact with the shaft 6 by downward motion imparted to the connecting rod 1'7 by the lever 16 actuated against the stop 42 as a fulcrum by the treadle rod 13.

In the drawings both gates are shown as transparent, but it will be understood that the lower gate may be of opaque material and the upper gate may have a transparent section to enable the operator to see the work. t5" While I havedescribed the preferred embodiment of my invention, it will be apparent that certain changes and modifications may be made thereto without departing from the spirit of the invention.

I claim:

1. The combination in a punch press having a throat; dies located in the throat; means for operating one of said dies; a cage closing the throat; two gates forming part of said cage, said gates being connected so that when one gate is turned down by the operator placing an article between the dies, the other gate will be raised; and means for disconnecting the trip mechanism actuated by one of said gates.

2. In a power driven punch press having a throat; a movable and a stationary die positioned in said throat; a cage enclosing the throat, a pair of pivotally mounted gates in said cage disposed one above the other to permit access to the dies, each of said gates being respectively pivoted to move in opposite directions; a clutch normally preventing movement of the movable die; a treadle operating said clutch and connected thereto by means of a lever; a stop normally ly" ing in the path of the said lever and acting as a fulcrum therefor to permit the release of the clutch mechanism, and means controlled by the opening of the gates for removing the stop from the path of the lever, making the operation of the treadle ineffective to release the clutch.

3. In a power driven punch press having a throat; a movable and a stationary die positioned in said throat; a cage enclosing the throat, a pair of pivotally mounted gates in said cage disposed one above the other to permit access to the 110 dies, one of said gates being transparent, each of i? said gates being respectively pivoted to move in opposite directions; a clutch normally preventing movement of the movable die; a treadle operating said clutch and connected thereto by means of a lever; a stop normally lying in the path of the said lever and acting as a fulcrum therefor to permit the release of the clutch mechanism, and means controlled by the opening of the gates for removing the stop from the path of the lever, making the operation of the treadle ineffective to release the clutch.

4. In a machine having a clutch, a clutch lever, an arm-pivotally mounted adjacent its center on the lower end of the clutch lever, means connected at one end of the arm for pivoting said arm and releasing the clutch, and manually controlled means movable into the path of the other end of the arm constituting a fulcrum about which the entire arm pivots to draw the clutch 130 lever downward and release the clutch permitting I 1 operation of the machine.

5. In a machine having a clutch, a clutch lever, an arm pivotally mounted adjacent its center on the lower end of the clutch lever, means connected at one end of the arm for pivoting said arm and releasing the clutch, a second arm, and means actuating said second arm into the path of the other end of the first mentioned arm and constituting a fulcrum about which said first arm pivots when actuated to release the clutch to permit operation of the machine.

6. In a press having a movable and a stationary die, a cage enclosing said dies, and a pair of pivotally mounted gates in said cage, disposed one above the other permitting access to the dies, each of said gates being respectively pivoted to move in opposite directions.

7.,In a punch press, the combination with a clutch and means for operating the same, of 150 means including a member movable into the path of said clutch operating means constituting a fulcrum for said means to effect release of the clutch and efiect operation of the machine, means operable to actuate the member out of the path of said clutch operating means to prevent release of said clutch, and means releasably connecting said movable member and its actuating means.

8. In a machine having a clutch, a clutch lever, an arm pivotally mounted adjacent its center on the lower end of the clutch lever, means connected at one end of the arm for pivoting said arm and releasing the clutch, a second arm, means actuating said second arm into the path of the other end of the first mentioned arm and constituting a fulcrum about which said first arm pivots when actuated to release the clutch to permit operation of the machine, and means releasably connecting said second arm and the actuating means.

9. In a punch press, the combination with a clutch and means for operating the same, of means including a member movable into the path of said clutch operating means constituting a fulcrum for said means to effect release of the clutch and effect operation of the machine, and means operable to actuate the member out of the path of said clutch operating means to prevent release of said clutch.

PAUL A. ERIKSEN. 

